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flags tweak for DIV with maximum negative value

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folkert van heusden 2024-04-04 23:01:15 +02:00
parent 5185df56eb
commit 27bd66fb20
Signed by untrusted user who does not match committer: folkert
GPG key ID: 6B6455EDFEED3BD1
1 changed files with 9 additions and 1 deletions
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10
cpu.cpp
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@ -643,6 +643,8 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
auto R2g = getGAM(dst_mode, dst_reg, wm_word, rm_cur);
int16_t divider = R2g.value.value();
int32_t R0R1 = (uint32_t(getRegister(reg)) << 16) | getRegister(reg | 1);
if (divider == 0) { // divide by zero
setPSW_n(false);
setPSW_z(true);
@ -651,8 +653,14 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
return true;
}
else if (divider == 0177777 && R0R1 == 0x80000000) { // maximum negative value; too big
setPSW_n(false);
setPSW_z(false);
setPSW_v(true);
setPSW_c(false);
int32_t R0R1 = (uint32_t(getRegister(reg)) << 16) | getRegister(reg | 1);
return true;
}
int32_t quot = R0R1 / divider;
uint16_t rem = R0R1 % divider;